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