I think the cycle is very interesting:
Colored (c 1920s etc) to Negro (c 1950s etc) to Afro-American (c 1970s) to African-American (c 1980s) to Black (c 1990s) to ........ [drum roll]......People of Color (c 2000s).
Whenever I hear the term "People of Color", I think of that cartoon "Doug" that was on Nickelodeon, the children's channel. Dougs friends were all colors - some were pink, some were purple, some were even green. :))