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