Website design has a part to play in SEO. A website with good design gets ranked higher than a site with bad design. Design is related to user exprience and user interface, which are important part of seo strategies.I don't think SEO is directly related to website design. SEO is an activity that you do in order to increase the ranking of your website in the resulting list of the search. If you have a standard design of your website and you do the SEO work then you can get free traffic from the search engines.