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