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