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