It might help to say what do you mean with "plotting graph using euler method" - euler method usually means numerical method to solve first order ODE - and if you mean this method, then solving ODE and plotting result are two rather separate things.
Anyway your equation is not a differential equation, you can transform it to an explicit form as
Anyway your equation is not a differential equation, you can transform it to an explicit form as
t = f(S) and then straigtly plot it with matplotlib as Larz60+ suggested. And if you instist on using implicit equation, there is plot_implicit() function in sympy.plotting.