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)(12,25)(13,30)(14,18)(15,19)(16,23)(17,28)(21,38)(22,33)(24,32)(26,37)(27,36)(29,35)(31,39)(34,40) involution — undirected(1,2)(3,7)(4,6)(5,8)(9,11)(10,16)(12,26)(13,24)(14,23)(15,22)(17,34)(18,33)(19,32)(20,30)(21,27)(25,31)(28,39)(29,40)(35,38)(36,37) involution — undirected(2,6)(3,4)(7,8)(9,12)(10,17)(11,21)(13,27)(14,28)(15,29)(16,31)(18,35)(19,36)(20,37)(22,39)(23,26)(24,40)(25,30)(32,38)(33,34) involution — undirected(11,22)(16,32)(20,33)(21,39)(23,24)(26,40)(31,38)(34,37) 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.