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