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