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