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