I don't think there is a sign for Olive, you can finger spell it if you need to, but I've just searched it up in the BSL dictionary and there isn't one.
Very sorry x
The sign for Alpaca is a bit like that, except you put your elbow ontop of your other arm and Do that sign, but with no movement.
Video here: https://youtu.be/G-txp8YBpCI
Hope this helps! x
My friend Dafid (Who is deaf)'s favourite colour is Cyan but doesn't know how to sign it, I thought I'd surprise him by finding out! Please let me know what it is, thanks x
-Kayla x