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