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