It sounds like you have real linoleum - not sheet vinyl, often confused with linoleum. The color fading is almost certainly caused by dishwasher solution damage. Linoleum is very susceptible to attack from alkalis - & Cascade (etc) is very alkaline. Unless you're handy with a marker pen or you want to make the floor light in color all over with Cascade you're a bit stuck. Do you have a rug you can put over it?