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