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