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