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