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