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)(11,21)(12,18)(13,14)(15,19)(16,20)(17,24)(22,23)(26,31)(27,32)(29,37)(35,39)(2,5)(3,8)(9,11,16,24)(10,17,20,21)(12,22,13,19)(14,23,18,15)(25,26)(27,28)(29,33)(30,31)(32,36)(34,35)(37,38)(39,40)(1,3,6,8)(2,7,5,4)(9,12,16,13)(10,18,20,14)(11,22,24,19)(15,21,23,17)(25,27,30,32)(26,28,31,36)(29,34,37,40)(33,35,38,39)(1,4)(2,3)(5,8)(6,7)(9,13,16,12)(10,18,20,14)(11,19,24,22)(15,21,23,17)(25,26)(27,28)(29,38)(30,31)(32,36)(33,37)(34,39)(35,40)(1,5,6,2)(3,4,8,7)(9,14,16,18)(10,13,20,12)(11,23,24,15)(17,19,21,22)(25,28)(26,32)(27,31)(29,39)(30,36)(33,34)(35,37)(38,40)(1,4)(2,3)(5,8)(6,7)(9,15,16,23)(10,19,20,22)(11,14,24,18)(12,21,13,17)(25,29)(26,33)(27,34)(28,35)(30,37)(31,38)(32,40)(36,39)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.