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