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