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