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