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