I'd say, maybe start off slow and test the water. You should really find out what the over-under is on people's opinions on trans people at your workplace. If the feedback if negative, then it's safer fo you to present as the sex they expect you to be. I'd say, maybe just figure out what they think first by peppering in the topic into casual conversation, i.e "So, I heard some stuff was happening to trans people lately. Crazy, right?" Once you get a consensus on how they think, then it's best to either present as who you are, or present how they expect from you, and indulge your lovely self at home, or at a social gathering with friends. The important thing to note, is that if they are conservative in a liberal city, it means that this place of work might be their last safe haven to express their prejudice and hatred. This might make them even more aggressively transphobic, and might make them react with extreme hostility if you come out to them. It's possible that they are not shitty people, but you need to find out first. It's not worth taking the risk, and being fired, or god forbid, murdered. Stay safe, and I hope the situation works out well for you.