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