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