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