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