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