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