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