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