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