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