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