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