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