It's called a "stacked area chart" and you can make them with something as simple as keynote, excel, google charts, etc. I just made our cohort graph yesterday

It's called a "stacked area chart" and you can make them with something as simple as keynote, excel, google charts, etc. I just made our cohort graph yesterday in keynote, based on data exported from Stripe. The input for the graph is a very simple table. One row for each cohort (or colored bar in the graph), and one column for each month in your timeline. In the cells you simply put the amount of revenue you earned from customers in each cohort in that month.