Make touch buttons transparent

I have made a game that uses touch buttons, but I don't want the buttons to be visible once the game starts and I can't seem to find any way to do it. I've made a simple script that sets the object with the 3 UI images in too inactive but this means the buttons no longer work. Can anyone help?

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class startGame : MonoBehaviour {
 
     public GameObject touchUI;
     public CanvasGroup touch;
     public GameObject startUI;
 
     void Start(){
 
         touchUI.SetActive (true);
         startUI.SetActive (true);
         Time.timeScale = (0.0f);
     }
 
 
     public void startGameClick(){
         
         touchUI.SetActive (false);
         startUI.SetActive (false);
         Time.timeScale = (1.0f);
     }
 }
 

Thanks Calum