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