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