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