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