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