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