I have been using this one since long, but forget to share it with you
The tarball contains a Ruby script to collect NUT data and a graph template; put the config.rb somewhere in your /usr/local/lib/site_ruby/1.x/, and the other script in to your cacti/scripts directory, import the graph template in to your working cacti.
You will need to pass on the UPS name/id as parameter like ups0@example.com to monitor it.
Image
Hope it is almost as useful to you as it is for me.
Cheers!