Darius Milhaud's "4 faces"

Smith's article reminded me of French composer Darius Milhaud's viola piece "the four faces." Milhaud was quite a bit earlier than Barthe and Sartre, so it might be stretch to impose the humanism ideas on him. This piece was supposedly written for a friend, each movement captures/portrays the face of a different woman from California, Paris, Wisconsin, and Brussel.

I am not sure where the eyes and the nose are in each movement, though I imagined Milhaud is perhaps portraying in a way that lines up with the Schopenhauerian concept of music representing the will and not the form, etc, etc. But I wonder if it is precisely because faces are thought of as representing some sort of underlying truth or character that allowed a composer to musically portray a face?