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