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