The fuel pump is located in the pump assembly module inside the fuel tank. There are plenty of photos of the pump and the entire assemby on line(such as parts stores) if you care to look them up.
The pump assembly module is accessed from the top of the fuel tank. In earlier models of your car you could access this by removing a plate on the rear floor of the car above the tank.. I am not sure if you can on your later model as in many vehicles you need to remove the fuel tank from the car to access the fuel pump assembly.

I am not sure what the person who referred you to a "fuel pump cap" really means. Perhaps you could get that person to explain what he meant. Possibly he actually meant the fuel cap on the fuel filler tube.