One of the reasons so many of us love tarot is the cards...we like to collect decks because we love the art. We love reading visual images (rather than words). In addition to the symbols, composition, and style in each of these tiny pieces of art, color plays an important role in how we respond to a card or to a spread.
Interpreting color as symbol can be tricky, as not all artists use the same sort of palate. However, artists create images meant to evoke certain responses and to do that they use the rules of design and also what they know of our responses to color. I don't always consciously scan a reading for color in order to interpret it, but I do know that as a reader I do respond