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