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