The film
The Violent Breed came out in 1976. The character's name was officially spelled Keoma, and it was a male, not a female, character. The film was a "spaghetti Western" made in Italy, and it is highly likely that the Italian screenwriters simply made up the name to sound "Native American" and that it is not actually a real given name in any Native American language.
http://www.imdb.com/title/tt0074740/