GoogleChart helps convert data to accept by google charts and draw it
cd my_cake_app/app
git clone git://github.com/imsamurai/cakephp-google-chart.git Plugin/GoogleChart
or if you use git add as submodule:
cd my_cake_app
git submodule add "git://github.com/imsamurai/cakephp-google-chart.git" "app/Plugin/GoogleChart"
then update submodules:
git submodule init
git submodule update
Check tests for usage examples