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)(11,19)(12,16)(13,17)(14,18)(15,20)(21,24)(22,23)(25,26)(27,32)(28,34)(29,38)(30,35)(31,33)(36,39)(37,40)(1,2)(3,5)(4,6)(7,8)(9,11)(10,15)(12,21)(13,23)(14,20)(16,17)(18,19)(22,24)(25,27,31,36)(26,32,33,39)(28,35,38,40)(29,37,34,30)(1,3,4,7)(2,5,6,8)(11,20)(13,21)(15,19)(17,24)(26,33)(27,36)(28,38)(30,37)(9,12)(10,16)(11,21)(13,20)(14,23)(15,17)(18,22)(19,24)(25,28,31,38)(26,34,33,29)(27,35,36,40)(30,39,37,32)(9,10)(11,15)(12,22)(13,17)(14,18)(16,23)(19,20)(21,24)(25,29,31,34)(26,28,33,38)(27,37,36,30)(32,35,39,40)(9,13,14,21)(10,17,18,24)(11,12,20,23)(15,22,19,16)(25,30,31,37)(26,35,33,40)(27,34,36,29)(28,39,38,32)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.