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