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)(13,14,19,23,20,24,18,22)(15,25,17,28,26,16,27,21)(5,6)(7,11)(8,10)(9,12)(13,15)(14,21)(16,23)(17,18)(19,27)(20,26)(22,25)(24,28) involution — undirected(2,4)(5,7)(6,9)(8,12)(10,11)(13,16,20,25)(14,17,24,27)(15,23,26,22)(18,28,19,21)(7,12)(9,11)(13,17,18,15,20,27,19,26)(14,21,22,16,24,28,23,25)(6,10)(9,11)(13,18,20,19)(14,22,24,23)(15,17,26,27)(16,21,25,28)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.