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