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