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