The large sphere collider is on the IgnoreRaycast layer. This is so the player can still interact with the world, without colliders blocking up raycasts.
I was thinking of OnMouseEnter, add some texture to that collider, but since it is on IgnoreRaycast layer, that didn’t work out.
It depends how you want to represent it in game? You could create a sphere or a cylinder that has no collider which is parented to the game object, and then set its radius to match that of the objects range. You’d need to make a semi transparent material and apply it to the sphere/cylinder so it doesn’t obscure anything. If you want an animated effect you could make a shader for it.
To give you an idea of what I mean you could draw a sphere with OnDrawGizmos() as a test: