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