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