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