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