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