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