Why does the Order of the phonex book describe Tonks' hair as bubblegum berwarna merah muda, merah muda and in the movie it's purple

They must have thought purple looked better. Maybe they tried a form of berwarna merah muda, merah muda and didn't like it. Did she have berwarna merah muda, merah muda hair at all in any of the films?

I think the same. But I've always thougth that it looks better this way