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