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