Showing (detailed) intervention effects graphically

I created an intervention with control group and experimental group. Both groups had pre- and post-tests. So I was using 4 graphs to explain in a presentation. (pre-test control, pre-test experiment & post-test control and post-test experiment) Each graph showed responses to a likert scale question with 5 options.

One of the listeners asked me if I could show the shift of 'how many' students had moved from one option in pre-test to some other option in post-test. I used pivot tables in excel and I am not sure how to proceed. from where I am at the moment. Can someone kindly guide me through this.

Thanking you in anticipation.

Best Wishes