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