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