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