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