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