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