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