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