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