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