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