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