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