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