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