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