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