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