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