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