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