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