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