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