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