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