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