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