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