Diffusion thermopower, Sd, is studied in pure suspended graphene (SG) monolayers in equipartition regime (for 100 K < T < 300 K). Electrons are considered to be scattered by the intrinsic in-plane and out-of-plane flexural acoustic phonons. Our numerical calculations of the temperature, T and carrier concentration, ns, dependences of electron mobility and Sd bring out the relative importance of the two scattering mechanisms in SG in the presence and absence of strain. For free-standing SG, Sd is found to vary almost linearly with temperature with dominant contribution from flexural phonons. This contribution is found to be suppressed in strained SG resulting in enhancement in mobility and reduction in Sd. Dependences of mobility and Sd on T and ns are modified. The relevance of Nordheim-Gorter rule in SG is also studied.