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