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