Sign languages are natural languages developed and used in all parts of the world where there are deaf people. Although different from each other, these languages, that have been exposed to varying degrees of communitisation and institutionalisation, share a significant number of common structures. As in the study of any other language, the linguistic study of visual-gestural languages, now a scientific field in its own right, faces the unavoidable problem of their graphical representation. This paper provides an overview, albeit non-exhaustive, of existing solutions to this challenge.