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