One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,3)(5,6)(7,8)(9,10)(11,12)(14,17)(18,20)(21,22,27,25)(23,24,28,26)(6,10)(7,11)(13,14)(15,18)(16,17)(19,20)(21,23)(22,26)(24,25)(27,28) involution — undirected(1,2,4,3)(6,10)(7,11)(15,19)(18,20)(21,24,27,26)(22,28,25,23)(5,7,9,11)(6,8,10,12)(13,15)(14,18)(16,19)(17,20)(21,25,27,22)(23,24,28,26)(1,3,4,2)(5,8)(6,11)(7,10)(9,12)(13,14)(15,18)(16,17)(19,20)(21,26,27,24)(22,28,25,23)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.