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