Contrary to popular belief, sign language is not a universal language. Like spoken languages, sign languages around the world are different.
International Sign (Language), formerly known as "Gestuno", is an artificially devised sign language. Gestuno is to Deaf as Esperanto is to Hearing.
Gestuno: International Sign Language of the Deaf (1975). World Federation of the Deaf. Hardcover. Out of publication(?).
Country Name-Signs (2003). World Federation of the Deaf.
Also see signed languages around the world.
For travelers: Gestuno.