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