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