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