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We demonstrate experimentally non-volatile, all-optical control of graphene's charge transport properties by virtue of a Fe:LiNbO3 photoconductive substrate. The substrate can register and sustain photo-induced charge distributions which modify locally the electrostatic environment of the graphene monolayer and allow spatial control of graphene resistivity. We present light-induced changes of graphene sheet resistivity as high as ∼370 Ω/sq (~ 2.6 fold increase) under spatially non-uniform light illumination. The light-induced modifications in the sheet resistivity are stable at room temperature but can be reversed by uniform illumination, or thermal annealing (100°C for 4 hours) thus restoring graphene's electrical properties to their initial, pre-illumination values. The process can be subsequently repeated by further spatially non-uniform illumination.