I'm on the other side of this: I'm a primary care doctor in a university medical school clinic. I have seen many of my colleagues in a professional setting. I'd actually advocating for, when possible, seeing a physician that you don't work with, but not for the reason you're thinking of.
I've done pap smears on two of my medical assistants. I delivered the babies of one of my medical assistants and three physicians in my department. The physical exams are so repetitive that, as other posters have said, your doctor isn't going to remember your body parts differently from the next person's. So physical embarrassment doesn't really enter the picture. I will put the caveat that I really DON'T think this is true for many--not all--male physicians and their female colleague patients. I've had this conversation with many doctors, and more men than women are uncomfortable doing pelvic exams on women they know in any social/professional capacity. Unfortunately, if our friends/colleagues ask us if we're willing to see them, we tend to chicken out and say "sure!" even when inside we're going "uh... I'd rather not".
The reason I advocate for seeing a physician outside your immediate workplace is because of I think you get better care. It is very difficult to separate what you know of someone socially from what you know of them medically. No matter how hard you try, you never really achieve full professional objectivity. For example, in the case of my pregnant MA, it's really normal to ask a prenatal patient about their substance use (medicines, drugs, alcohol, smoking). Maybe my MA will feel uncomfortable admitting that she's smoking the occasional cigarette. Maybe she doesn't tell me when I ask, because she's heard me casually whine about pregnant smokers before. Or maybe I don't even bother asking her, because hey, I've known her for years, and I've never smelled cigarette smoke on her. Either way, her medical care is less thorough.
Or maybe we do her routine labs and find out she has chlamydia. I treat her with antibiotics, obviously, but now she's really embarrassed that I know, and worse yet, the clerk who took the result off the fax machine and put it in my mailbox probably knows too. Then she's too embarrassed to get the followup test a month later to make sure she's cured, because then yet another clerk will probably see the result, so she doesn't get it done, and we never figure out that the infection didn't get treated and she needed more antibiotics. Then she goes into preterm labor because of the infection.
Or maybe she has a not-dangerous, but still bothersome problem. She has a long, protracted labor, is in a lot of pain, and her epidural isn't working very well. She's my friend, and she knows that I've been averaging about 3 hours of sleep per night because of my own baby at home. So instead of having me paged at 2:30 AM to help her with her pain, she just suffers silently, while it never would have occurred to her NOT to wake up the on-call doctor she never met before.
That kind of thing happens a lot. No one means to be anything less than objective, but unconscious biases slip in. I'd encourage you to think about working with a doctor who's a stranger simply because I think the medical care is better. When my colleagues ask me where they should go, I recommend a close-by clinic, not affiliated with our system, where I know the docs really well and trust them.
On the other hand... your PCP really doesn't remember what your vagina looks like. She's seen hundreds, maybe thousands, and none of them are that interesting.