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