A search for "power transistor" in frtizing parts search turns up pnp and npn power transistors in a TO220 case. The schematic is a single transistor rather than darlington though so if you want an accurate schematic you would need to create a custom part and modify the schematic svg to darlington. However a quick google search indicates there is a tip120 available in the adafruit fritzing library available on github as well which may have a correct schematic. I'd try their first as it indeed has the darlington schematic although it is pnp. If you need the npn it should be simple to modify that part to be npn (I can do it for you if you need it).
Peter