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