The word in which the 's' appears may influence the pronunciation.
[We could move this question to the Other Languages forum. In that forum, people who know Vietnamese may be able to help you by comparing the English s to the Vietnamese s. If you want us to do this, please report this thread and ask us to move the thread and add Vietnamese to the title.]
Nope, the pronunciation of the letter 's' in English is different from the one in Vietnamese. And even in English, it can be pronounced differently.
To some extent, the letter "s" in Vietnamese can be pronounced as the "sh" in English like how you pronounce the word English. However, this is the standard Vietnamese pronunciation. What I wrote doesn't take into account the different way of pronouncing it in different regions of the country (southern or middle part mainly as I come from the northern part of Vietnam)