{The Little Book of Colour: How to Use the Psychology of Colour to Transform Your Life} by Karen Haller

Color Psychology: A Full Guide by Nick Kolenda - Also worth checking out his other free guides. The guide on Visual Attention would be a good follow-up after reading about color. His guides are a gold mine if you're interested in persuasion.

{Evil by Design: Interaction Design to Lead Us into Temptation} by Chris Nodder - While not specifically about color, this book talks about the tricks websites use to nudge users into buying.

Hope this helps.