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