S-type and the Taurus were built off of the same platform, so there’s bound to be some familial resemblance. But no doubt many cars look alike these days. Only so much you can do with a rounded, aerodynamic blob...
S-type was built on the DEW98 platform, which served as the basis for the Lincoln LS and Ford Thunderbird.
The Taurus was on the D186 platform through 2007. This was shared with the Mercury Sable, Lincoln Continental, and Ford Windstar.
The new Taurus is on the D3 platform, which is/was used for the Sable, Taurus X / Freestyle, Mercury Montego, Volvo S80, Volvo V70, Volvo XC70, Volvo S60, Volvo XC90, and the upcoming Lincoln MKS....
The D3 was based off the Volvo P2, which was designed by Volvo prior to Ford’s buyout of Volvo, and which debuted in 1999.... the D3 and DEW98 are unrelated....