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