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