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