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