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