OK. Tricky.
OK, first of all, the attached chromatograms don't look exactly the same to me. Maybe you expected more differences, but we don't know your method parameters. With those, and expert (not me) may be able to help.
You don't have a diesel standard. Since diesel fuel may or may not have a standard, given its likely a mixture, you may have to search more carefully. We'll save that for later.
Do you have a palm oil standard? You can see if that shows what you need. You can also spike more palm oil into your unknown, to see if peaks get bigger. That will help you identify what you're looking for. Spiking also helps quantitation. Example: you think you have 7%, you add palm oil until you have 10% and 17%, not only do you see what, but you see how much response matches 7% more.
Also I'm lest wondering what you actually have. Do you have diesel mixed with 7% palm oil, because that will work just fine, but only in a warmed up, carefully tuned diesel engine. Or do you have diesel fuel that is 7% made of aliphatic esters derived from palm oil, because that is a separate question.