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