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