Using the standard way of representation:
Here we have a rotation followed by an inversion (technically called 'rotational inversion'). So as to represent it, what I have done is:
1) Both rotation and inversion occur for the first time. The circle changes of plane:
2) Both rotation and inversion occur for the second time. The circle changes of plane again:
My issue is that I am not convinced of this, because in theory there is rotation followed by an inversion and they do not happen simultaneously. So if this is wrong, what is the correct representation and why?
Diagram for $\bar 3$
Diagram for $\bar 6$
NOTE: I have used comma to stress there was an inversion