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