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