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