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