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