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