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