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