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