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