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