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