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