That picture looks like a cartoon....sorry if it offends but that is just what it looks like. There is no way the artist knew what Elijah looked like....just another portrait of some mans imagination of what he determined....thus it is with many of the artists of history.
No offense taken. An Icon is a representation of Christ or of a Saint that uses particular stylistic rules - for the particular reason that we don't know what many of them looked like. It's not a naturalistic portrait as most artists would attempt to do - it might be more appropriate to call it a "theological portrait"
Unfortunately, I don't feel sufficiently educated on the matter to comment more on it... but I could point you in the direction of one of the Eastern Orthodox posters if you're interested in learning more.