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