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