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