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