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