The petroleum industry is generally offers the best salary for engineering graduates who want to continue working in engineering. So you're looking at the likes of BP, Shell, ExxonMobil, Chevron, Marathon, BG Group, Maersk Oil, Apache, Nexen, Talisman, ConocoPhillips, Saudi Aramco, Statoil, etc. - the companies that have licenses to explore and produce petroleum. These companies also usually offer lots of travel, too, as they have offices and work all over the world.
There's also the oilfield services companies like Baker Hughes, Schlumberger, Haliburton, Wood Group, Weatherford, Petrofac, Aker, FMC and the like. These will give engineering graduates more technical, design orientated work which will probably closer resemble university engineering. The big oilfield services companies are also global so you can work all over the world with them, too.
Then there's the utilities sector, with companies like EDF, E.ON, Scottish and Southern Energy, etc. Their salaries tend to be slightly lower than the above, but not everyone wants to work in oil - in fact it appears most don't, if the skills shortage is anything to go by.
There's also manufacturing and automotive. I know pretty much **** all about these companies so I won't say anything about them.