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