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