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