Diana Olivia Winifred Maud Cooper, Viscountess Norwich, née Lady Diana Manners (1892-1986) was one of those society beauties who was too attractive to capture with oil or any other kind of paints. Not that a few artists didn't try, and some of their efforts are shown below.
On the other hand, cameras love certain kinds of beauty (and vice-versa, I assume). So the best images of Lady Diana Cooper seem to come via photography, as also can be seen below. The photo at the top of this post is by Emil Otto Hoppé (1878-1972), and is perhaps the iconic image of Diana.
Her Wikipedia entry is here, and views of how she lived can be found here.