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