Born in Marseille, Diana is the son of a boilermaker whom he admires and whom he follows from a very young age in port and industrial circles. This marks his political commitment and a large part of his artistic work. He belongs in particular to the groups of "Proletarian painters" and "People's painters". He participated in the creation of the first provincial Maison de la Culture, supported by Louis Aragon, André Malraux and Jean Giono.
We find in his style fauvism, expressionism, realism, sometimes naive art, while maintaining an original line. Diana rubs shoulders with the painters Louis Toncini, Pierre Ambrogiani and Antoine Serra. After the Second World War, he was appointed professor at the École des Beaux-Arts.