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