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