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