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