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