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)(13,14,18,21,17,19,27,24)(15,20,23,16,22,26,28,25)(5,7)(6,9)(8,12)(10,11)(14,19)(15,22)(21,24)(23,28) involution — undirected(1,2,3,4)(6,10)(9,11)(13,15,17,22)(14,20,19,26)(16,24,25,21)(18,23,27,28)(7,12)(9,11)(14,19)(15,22)(21,24)(23,28) involution — undirected(6,10)(9,11)(13,16,18,26,17,25,27,20)(14,15,21,23,19,22,24,28)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.