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)(13,14,15,20,17,21,23,18)(16,24,25,28,26,27,22,19)(2,3)(5,6)(7,11)(8,10)(9,12)(13,15,17,23)(14,18,21,20)(16,25,26,22)(19,27,28,24)(5,7)(6,9)(8,12)(10,11)(13,16)(14,19)(15,22)(17,26)(18,24)(20,27)(21,28)(23,25) involution — undirected(1,3,4,2)(7,12)(9,11)(13,15,17,23)(14,20,21,18)(16,25,26,22)(19,24,28,27)(6,10)(9,11)(13,15,17,23)(14,18,21,20)(16,22,26,25)(19,24,28,27)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.