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