There are different makers and versions of EGPWS, with different options, so what I say here may not specifically apply to each aircraft with EGPWS. However, to answer your question: no, with basic EGPWS, you won't normally get an "outline" of an island or coastline*
As NONE says, it's not a radar depiction. Rather, it uses information from three different databases (terrain, obstacle, and airport) to give you a display.
This display will normally show terrain within 2000' below the aircraft altitude. There are other features which will show high terrain, if you're in a high terrain area, regardless of the relationship of terrain height to aircraft altitude.
*There are exceptions to this:
a) if you're flying low enough to be within 2000 of the coastline, for example, or
b) there are some types of EGPWS features/options/interface software which WILL show both water and terrain (therefore, in effect generating a depiction of a shoreline). However, I've not flown in an aircraft which uses that sort of EGPWS feature, and I don't know which airlines/aircraft do have it.