The Shillong was a Cargo Liner of 8,934 GRT built at Vickers-Armstrong & Co Ltd and launched on 9th June 1948.
Many of the regular tour operators in the Red Sea state that the wreck of the Shillong has not been found as of late 2008. Other dive operators state on their websites that the wreck is on their dive itineraries.
This does however have one of the most dramatic incidents of all Red Sea Wrecks which you can read about at: http://dive.im/TheShillong