A better tool would be something like mxGraph, which allows for UML/Architecture diagramming in an easier way. (https://jgraph.github.io/mxgraph/)

Hackerrank (I work here) has included this in the remote/pair programming service. You can run it by going to https://www.hackerrank.com/products/codepair and clicking "Start session", and sharing with the ther user.