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