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