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