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