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