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