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