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