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