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