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