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