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