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