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