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