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