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