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