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