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