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)(14,18)(16,20)(19,24)(21,25)(23,27)(26,28)(6,9)(7,11)(14,19)(18,24)(21,26)(25,28) involution — undirected(13,14,20,24,17,19,16,18)(15,21,27,28,22,26,23,25)(5,7,8,11)(6,10,9,12)(13,15)(14,21)(16,23)(17,22)(18,25)(19,26)(20,27)(24,28)(1,3,4,2)(6,9)(10,12)(14,19)(15,22)(18,24)(23,27)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.