The Greek ἴον is both the flower and its color, as in English, so my best guess is that West was going for flowers. ("She wants to be flowers, but you make her owls. Always it is owls . . .") But I still think a Muse with a lapful of violets—or a chain of violets over her breast—is a much more powerful image than, she smells nice. Even if she smells like violets.