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