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