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