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