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