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