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