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