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