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