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