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