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)(11,12)(13,15)(14,16)(18,22)(19,20)(25,26,30,27)(28,33,36,31)(29,34,38,32)(35,39,37,40)(2,6)(3,8)(9,11,14,15)(10,13,16,12)(17,18,21,22)(19,24,20,23)(26,27)(31,33)(32,34)(39,40)(1,3)(2,7)(4,6)(5,8)(9,12,14,13)(10,15,16,11)(17,19,21,20)(18,23,22,24)(25,27,30,26)(28,33,36,31)(29,34,38,32)(35,40,37,39)(1,3)(2,4)(5,8)(6,7)(9,13,14,12)(10,15,16,11)(17,18)(19,23)(20,24)(21,22)(25,28)(26,31)(27,33)(29,37)(30,36)(32,40)(34,39)(35,38)(1,4)(2,8)(3,6)(5,7)(9,10)(11,13)(12,15)(14,16)(17,20,21,19)(18,23,22,24)(25,29)(26,32)(27,34)(28,35)(30,38)(31,39)(33,40)(36,37)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.