The Graph plugin sources "graph" data as might other plugins eventually. This script merges this data to be drawn with Graphviz. github 
Input is from lineup items that source "graph" data. All found will be merged.
A summary of connections shows. Then 'draw' opens a new page with Graphviz rendering via dot format markup.
Old Graphviz transport now coded client-side.
Sun --> Earth --> Moon Sun --> Mars Sun --> Jupiter --> Europa Jupiter --> Io
http://hatfield.asia.wiki.org/assets/pages/lineup-overview/diagram.html HEIGHT 300