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