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