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