I have found a couple of pictures on the web, and as they are said to be 'public domain' take the opportunity of reproducing them here. The one above is supposed to be Edmund of Langley, first Duke of York. Quite a handsome fellow, I think. Presumably this is where Constance got her good looks.
Needless to add, the second one is of Edward of York, at various times Earl of Rutland, Duke of Aumale, and second Duke of York. Would you buy a used destrier from this man?
I'd not bet above 1p (one new penny) that these images are authentic; at best they might be based on a lost original. More likely they came out of some Victorian's imagination. But I suppose they are better than nothing - just.