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