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