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