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