One vertex per element, one color per generator, with an edge from x to x·s.
(1,2) involution — undirected(4,7,8,9)(11,12,16,20,17,13,15,19)(14,18,22,25,23,21,24,26)(3,4)(5,9)(6,8)(7,10)(11,13)(12,17)(14,21)(15,20)(16,19)(18,23)(22,26)(24,25) involution — undirected(11,14,17,23)(12,18,13,21)(15,24,16,22)(19,26,20,25)(11,15,17,16)(12,19,13,20)(14,22,23,24)(18,25,21,26)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.