The variations in the different body types result in different highlights and lowlights expressing the hue (hues in UO exist with a variety of colors in a single hue) in the different ways as we see in your screenshot. It's all randomly generated. I also was incorrect in my previous statement, upon further investigation it's actually 54! different hues that are possible, however the variations between some are so slight they essentially look the same. Apologies for the confusion!