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