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