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