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