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