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)(15,22)(16,17)(18,25)(19,21)(20,23)(24,27)(26,28)(6,9)(7,11)(13,15,18,23,19,24,17,26)(14,20,16,22,21,28,25,27)(2,4)(5,6)(7,10)(8,9)(11,12) involution — undirected(6,9)(10,12)(13,16,19,25)(14,17,21,18)(15,20,24,28)(22,23,27,26)(5,7,8,11)(6,10,9,12)(13,17,19,18)(14,16,21,25)(15,23,24,26)(20,27,28,22)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.