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