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