One vertex per element, one color per generator, with an edge from x to x·s.
(5,8)(9,10)(11,16)(12,17)(13,22)(14,18)(15,19)(20,23)(21,24)(25,26,30,33)(27,35,36,39)(28,31,29,34)(32,37,40,38)(1,2)(3,5)(4,6)(7,8)(9,11)(10,15)(12,19)(13,21)(14,20)(16,22)(17,23)(18,24)(26,31)(28,29)(32,39)(33,34)(35,40)(37,38) involution — undirected(1,3,4,7)(2,5,6,8)(9,11)(10,16)(12,21)(13,19)(14,20)(15,22)(17,24)(18,23)(25,27,30,36)(26,32,33,40)(28,38,29,37)(31,39,34,35)(9,12,14,13)(10,17,18,22)(11,19,20,21)(15,23,24,16)(26,33)(27,36)(31,34)(37,38)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.