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