To be honest, I would recommend any book by Todd Parr. His books are wonderfully illustrated and have meaningful themes. Parr might be best known for his book, It's O.k. to be Different, which is a beautiful celebration of differences. The Family Book is similar in theme, but focuses on the wide variety of family configurations that exist. Parr's book literally show people of all colors, but also uses animals to help children understand the complexities of diversity. Check out The Family Book on Amazon.
Check out author Todd Parr's website!