I'm trying to setup habit tracking on org but can't see any consistency
graph.

I have setup a simple TODO item and set the style as habit by using C-c C-x
p (org-set-property).

* TODO exercise
  SCHEDULED: <2013-12-03 Tue .+1d>
  - State "DONE"       from "TODO"       [2013-12-02 Mon 17:31]
  - State "DONE"       from "TODO"       [2013-12-02 Mon 17:30]
  :PROPERTIES:
  :LAST_REPEAT: [2013-12-02 Mon 17:31]
  :STYLE:    habit
  :END:

Orgmode version is 8.2.3c (20131202)

Thanks.