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)(13,14,16,21,17,20,26,19)(15,22,25,28,23,18,24,27)(1,2,4,3)(5,7,10,11,8,12,9,6)(13,15,16,25,17,23,26,24)(14,18,21,27,20,22,19,28)(6,7)(9,10)(11,12)(14,19)(15,23)(16,26)(18,27)(20,21)(22,28) involution — undirected(1,3,4,2)(6,11)(7,12)(13,16,17,26)(14,19,20,21)(15,24,23,25)(18,27,22,28)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.