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