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