You would be required to make a script that loops through the all the gui buttons and assign a specific gamepad input to it. Example: Enum.KeyCode.ButtonX (Which assigns it to the “X” button on the xbox controller). After assigning, you can make a table of functions to toggle the UI and call the function needed according to the input.
(Also make sure to only run this if the player is on Xbox, refer to @JackscarIitt 's reply for how to do it)