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