you can change the color of the categories using
HTML Code:
.post-footer a {color: #00ffff !important; }
but this will change the entire line and if there are multiple categories, they will all be the same color. There is no unique identifier being generated.
You might be able to go into the code and add a 'class=' and then the category name to the <a> that is generated and then specify a css selector for each category.