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