Suteki is a Japanese word, said to be composed of the su from subarashii 'wonderful' followed by the suffix -teki. In any case, it is usually written in Chinese characters. This has been arbitrarily assigned to writen the word suteki -- that is, there is no etymological basis for writing it this way.
The following photo, taken in the Osaka subway, shows suteki written in Chinese characters:
A subway station in Osaka sported the following sign, obviously as part of the same campaign. However, suteki is written in hiragana as :
A Google search in September 2003 revealed the following distribution for suteki: