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