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