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