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)(11,21)(12,19)(13,18)(14,17)(15,20)(16,24)(22,32)(23,37)(25,31)(26,40)(27,34)(28,33)(29,36)(30,39)(35,38) involution — undirected(1,3)(2,5)(4,8)(6,7)(9,11,13,24)(10,16,18,21)(12,26,27,38)(14,25,15,22)(17,32,20,31)(19,35,34,40)(23,28,39,29)(30,33,37,36)(10,17)(11,22)(14,15)(18,20)(19,33)(23,38)(24,25)(26,39)(28,29)(31,32)(34,36)(35,40) involution — undirected(2,6)(5,7)(10,18)(12,27)(16,21)(17,20)(23,39)(26,38)(28,29)(31,32) involution — undirected(3,8)(5,7)(9,12)(10,19)(11,23)(13,27)(14,28)(15,29)(16,30)(17,33)(18,34)(20,36)(21,37)(22,38)(24,39)(25,26)(31,40)(32,35) 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.