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