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