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)(13,14,20,23,19,15,18,17)(16,21,27,28,25,22,26,24)(5,6)(7,11)(8,10)(9,12)(13,15,19,14)(16,22,25,21)(17,20,23,18)(24,27,28,26)(2,4)(5,7)(6,9)(8,12)(10,11)(13,16)(14,21)(15,22)(17,24)(18,26)(19,25)(20,27)(23,28) involution — undirected(7,12)(9,11)(13,17,18,15,19,23,20,14)(16,24,26,22,25,28,27,21)(6,10)(9,11)(16,25)(21,22)(24,28)(26,27) 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.