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