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