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