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)(13,14)(15,23)(16,21)(17,22)(18,19)(20,24)(25,27)(26,28) involution — undirected(1,2)(3,4)(5,6)(7,11)(8,10)(9,12)(13,15,17,18)(14,19,22,23)(16,24,26,25)(20,21,27,28)(5,7,8,12)(6,9,10,11)(13,16,17,26)(14,20,22,27)(15,24,18,25)(19,21,23,28)(2,4)(7,12)(9,11)(13,16)(14,21)(15,25)(17,26)(18,24)(19,20)(22,28)(23,27) involution — undirected(6,10)(9,11)(16,26)(20,27)(21,28)(24,25) 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.