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