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