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