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