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