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