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