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