Q. How much energy does it take to create a photon?
A. ħω, where ω is the frequency of the photon.
Q. How much energy does it take to create a graviton?
A. Exactly the same, ħω.
Q. Well then, how come particle colliders create scads of photons but no gravitons?
A. It's not the energy that's the problem, it's the production rate. Photons are produced (primarily) by time-dependent electric dipoles. Gravitons are mainly produced by time-varying mass quadrupoles. You can crash two protons together and calculate their mass quadrupole moment as they collide, and then multiply that by the gravitational constant G to get the production rate. It's ridiculously small.
Q. What does the Planck mass have to do with it, if anything?
A. The Planck mass is the energy at which (presumably) gravitational interactions become comparable to the strong and weak interactions. So yes, you'd need a collider with that energy if you wanted to make the production rates comparable. But spacetime literally goes to pieces at that energy. If you really want to make gravitons, run at a much lower energy and be prepared to wait.