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