The song is also titled "Adagio for Strings",Opus 11 by the American composer Samuel Barber. It was also used in the Oliver Stone film "Platoon". If you go to iTunes and search for "Adagio for Strings" you will see many versions of this piece. It's also known as "Barber's Adagio.
The song is just called the Elephant Man Theme and it can be found on the soundtrack to the movie which is available at Amazon.com. The link is below: