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