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