Here is a sticky vinyl stencil I use to repaint in yellow the top of the power steering canister with the original, Nur Automatic Transmission Fluid.
Paint the canister top black and then after drying, cut the vinyl to a small piece and place the stencil on top. Paint the yellow by hand brushing a couple of layers or spraying it. Just peel off after drying. It will not damage the black paint when you pull it off slowly.