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