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