If there are M lines of latitude (horizontal) and N lines of longitude (vertical), then put dots at
(x, y, z) = (sin(Pi * m/M) cos(2Pi * n/N), sin(Pi * m/M) sin(2Pi * n/N), cos(Pi * m/M))
for each m in { 0, …, M } and n in { 0, …, N-1 } and draw the line segments between the dots, accordingly.
edit: maybe adjust M by 1 or 2 as required, because you should decide whether or not to count “latitude lines” at the poles