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