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