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