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