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