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