Where can I find the connectivity matrix of the connectome of C. Elegans?
The full connectome of C. elegans (Fig. 1.) is described by Farber (2012) and as far as I know, the most complete data on C. elegans, including its connectome is available from the OpenWorm Project found here.   


Fig. 1. C. elegans connectome. image source: Farber (2012)

Reference
- Farber, Sci Am February 2012  

Further reading
- Are there organisms with fewer than 1000 neurons?