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