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