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