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