There are generic representations of controllers using numbers and describers, like this one:
If you dont want to create sprite sheets for the most common controller types you would at least need a screen or menu where the player sees a schema like the above. When the player then presses, the according part of the controller should light up. Why ?
Even if controllers seem similar they are very different. Sometimes the DPAD and the left stick is swapped, sometimes the button axis 1,2,3,4 are in a differen arrangement. If you support many controllers there is always the chance to encounter some off-brand design so it would make sense to have a space where the user can align their controller to your input mapping.
If every character has the same moves it would even be pretty cool to have a small character in that configuration menu that performs the according action when the button is highlighted.