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