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