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