I read Mouse Paint in preschool story hour this morning. The first page shows 3 white mice stading on a piece of white paper and the cat can't find them. I asked a 5 year old "why can't the cat see them?" and he told me "they're camoflauged!"
Mouse Paint is a great introduction to color for young children. It shows the primary colors, red, yellow and blue and what happens when the mice paint themselves and then mix the colors together to make new ones. It reinforces the paint mixing when they paint the white paper always keeping in mind they need a white space because of the cat.