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