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