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