Change product image on changing color of the product

I have been struggling to change the image of the product on changing the color of the product on product detail page. I am not able to find the solution on how it will change the image on selecting the color.
For example, I have a configured the product with 3 variations, black, white, blue.
by default, product image appears. but when the user changes the color to blue, the product should display the blue color product(added already to the backend by making it configurable).
I have a custom theme and I am not overriding the templates.
Any idea any help would save me