One vertex per element, one color per generator, with an edge from x to x·s.
(1,2) involution — undirected(3,4) involution — undirected(5,6) involution — undirected(8,10)(12,16)(13,19)(14,22)(24,26) involution — undirected(11,12,15,16)(13,20,19,17)(14,18,22,23)(21,26,25,24)(7,8)(9,10)(11,13,15,19)(12,17,16,20)(14,21,22,25)(18,24,23,26)(11,14)(12,18)(13,21)(15,22)(16,23)(17,24)(19,25)(20,26) involution — undirectedA 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.