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