I think it is not difficult at all. You need to prepare a paste from griphite powder and a non-interfering mulling agent like oils used in IR. The pasted then is casted in a mold under high pressure and left to dry.
I remember thath there is a good chapter in electrochemistry Peter Kissinger's book on carbon electrodes. Another good book especially on practicle issues is the book of Sawer "Electrochemistry for chemists"
Cf.: Hugh O. Pierson, Handbook of Carbon, Graphite, Diamond and Fullerenes ─ Properties, Processing and Applications, Noyes Publications, New Jersey, 1994, Section 5: "Molded graphite: Processing, properties, and applications".