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