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