I am unsure what some of the graphs measure and labels mean when viewing the demo. Tooltips, descriptions, etc would be helpful in my opinion. Overall it seems like a great start though.
For all PGSQL graphs, the signification of each graph and label is (only :/) documented in the check_pgactivity "--help" option, as it's the direct source of these graphs. Sadly, we didn't have time yet to write a proper documentation on the wiki page, or on the UI. We'll add a better documentation as soon as possible.
For the SYSTM graphs, they correspond to standard nagios system checks.
