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