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