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