How can I add an image icon to a category

I have made custom post types for "Vendors". I am displaying them on a custom template- "page-vendor". I have them sorting by category, not custom taxonomy, and I need to differentiate the category "featured Vendor" with either an image icon on the top right of the post, and/or a different background color. I have googled till I am almost dead- and nothing really helps. Is there an answer to this?