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