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