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