There is a small number of items, labeled say as 1, 2, 3, 4, 5.
There are several arrows between items like 4->2.
I want to visualize this digraph diagram.
I want the software to do it as much automatically as possible. I want it to be WYSIWYG. I do not want to paint the arrows manually, if possible, but just point the start vertex and end vertex.
Now, shame to say it, I use a paper and pen.
Ubuntu Linux 18.04.