Draw lines through the point in the direction of those eigenvectors. Since you say the eigenvalues tell us that the point is a saddle point, there must be one positive and one negative eigenvalue. Draw an "arrow" pointing away from the point on the line corresponding to the positive eigenvalue and an "arrow" pointing toward the point on the line corresponding to the negative eigenvalue. The "flow" lines around the point will lie within those lines and their direction will be the same as on the lines near them.