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)(11,12)(13,18)(14,16)(15,17)(19,20)(21,23)(22,24)(25,26,31,35)(27,32,30,34)(28,29,33,40)(36,37,38,39)(1,2)(3,6)(4,7)(5,8)(9,11)(10,15)(12,16)(13,19)(14,17)(18,22)(20,23)(21,24)(25,27,31,30)(26,32,35,34)(28,36,33,38)(29,37,40,39)(1,3,5,4)(2,6,8,7)(10,16)(11,17)(13,21)(20,22)(27,30)(32,34)(36,38)(37,39)(1,3,5,4)(2,6,8,7)(9,11)(10,12)(13,19)(14,17)(15,16)(18,20)(21,24)(22,23)(25,28)(26,29)(27,36)(30,38)(31,33)(32,37)(34,39)(35,40)(1,4,5,3)(2,7,8,6)(9,12)(10,17)(11,16)(13,20)(14,15)(18,24)(19,23)(21,22)(25,29)(26,33)(27,37)(28,35)(30,39)(31,40)(32,38)(34,36)(9,13,14,21)(10,18,16,23)(11,19,17,24)(12,20,15,22)(25,30,31,27)(26,34,35,32)(28,38,33,36)(29,39,40,37)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.