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