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