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