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