(The largest known mountain is Mount Olympus on Mars, by the way. It is 16 miles high and larger at its base than the entire state of Arizona.)
You can see an interesting modeled image of the Vesta mountain here:
but please note that the height of everything on this picture has been exaggerated by a factor of 1.5 to make the huge mountain look more mountain-like, as it was posing for the media and the public.
We expect many more discoveries about asteroid Vesta as the DAWN mission continues.