You got me- anything permanent is going to look a bit unnatural. Plus, the only thing that's going to absolve you of liability (assuming you're avoiding the marks) is having DigSafe/ Miss Utility/ whomever mark your utilities before you dig.

It's free and only requires 48 hours of advanced planning. I'd just call for a re-mark before digging. If you want a permanent record for planning purposes, I guess you could do what we did to mark property lines in New England, and set a chunk of flat granite level with the ground at intervals. Just know that frost will heave the granite up, high enough to catch the blade on your mower.

Remarking is probably the surest and best.

I've kept a scrap of paper with a rough diagram taped to the inside of a cabinet - # of feet to anything buried from fixed points. Works for me.

What cables are buried, and how deep are they? A more expensive but alternative solution would be to re route anything in an area you are likely to prod on a regular basis.

I marked mine with plastic tent stakes (from Walmart)driven all the way into the ground. They are a yellowish color and when I need to find the location of the phone/gas lines I just dig around until the tops are uncovered and run a string on a regular stake from point to point .