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