Data Wrangling was done beforehand to transform the subscriber data from horizontal to vertical format so that Power BI can group and display total subscribers for each categories.
We have also tried different Network Graph Visuals from Power BI's AppSource, and we found that the ZoomCharts Network Chart is the only one that allows multiple categories of nodes. We are only using the Free version so a lot of customization is not allowed.
Please refer to this link for a short introduction to our visualization: Quick Introduction