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