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