Quantum optical lithography, a diffraction-unlimited method, was applied to pattern monolayer graphene at 10 nm resolution. In our tests with chemical vapor deposition monolayer graphene samples, we have succeeded in producing flat surfaces of a sandwich of monolayer graphene-resist on Si, Si3N4, or glass substrates. Complex patterns have been written on monolayer graphene samples by a nanoablation process. The method could be used to realize monolayer graphene nanodevices.