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)(11,12,17,20)(13,16,22,21)(18,19,23,24)(25,26)(27,29)(28,33)(30,34)(31,35)(32,37)(36,39)(38,40)(1,3,5,8)(2,6,4,7)(9,10)(11,12)(13,21)(14,15)(16,22)(17,20)(18,24)(19,23)(25,27,31,37)(26,32,35,29)(28,38,30,36)(33,39,34,40)(10,15)(11,17)(13,22)(19,24)(25,28,31,30)(26,33,35,34)(27,36,37,38)(29,39,32,40)(9,11,14,17)(10,12,15,20)(13,18,22,23)(16,19,21,24)(25,29)(26,27)(28,39)(30,40)(31,32)(33,36)(34,38)(35,37)(1,2,5,4)(3,6,8,7)(9,12)(10,11)(13,19)(14,20)(15,17)(16,18)(21,23)(22,24)(25,30,31,28)(26,34,35,33)(27,36,37,38)(29,39,32,40)(1,4,5,2)(3,7,8,6)(9,13)(10,16)(11,18)(12,19)(14,22)(15,21)(17,23)(20,24)(25,27)(26,29)(28,38)(30,36)(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.