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