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