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