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