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