Well the story I have gathered from reliable sources (Cunninghams own promo site) is...

Cunningham wanted to do a concept video but had no name in the industry in 97. So he called up a local club DJ by the name of Richard James who was busy spinning ambient house and trance.

The conversation was something like....
hey I am making a video
Cool whats it about?
I don't really know yet, got any original work I can use to build it off of?
Give me a couple weeks and I can come up with something.
Ok see you then.

So Richard James picked the name Aphex Twin after some inside joke (unverified story) and handed Cunningham the music he had made. They finalized down to a single album of 5 songs (I think) which was different than any other music James had ever done. More intricate and bordering on "noise" rather than the ambient he had been used to doing.

So the video was made using Richard James' face as a marketing device and continues to appear in all of his videos on children, hot chicks, strange creatures etc. and has become a trademark signature.

Effectivley that single video launched two careers for two very interesting artists.