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