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