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