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