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