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