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