The costumes should convey a tribal feel, but using a contemporary design. bright colors, but with earth tones.
Here’s some ideas from West Side Story, both old and new versions. These are pictures of the Sharks gang, which is Puerto Rican. Their gang color is purple and the palette is earthy.
Costume Library
Women’s palette
Men’s palette
Note that pants need not be black. khaki, blue, and other palette colors may be used. Vests are optional. Headgear, such as sweatbands, are possibilities as well.