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