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