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