AUG ES options are still trading today. With that in mind, here were my two diagonal trades for the month. This is for illustrative purposes only. I do not claim any expertise with this strategy. My normal trades are about as subtle as a rhino horn up the backside 
7/25 ES 1277 VIX 14.3
STO AUG 1240P @ 6.00 delta 0.219
BTO SEP 1200P @ 7.00 delta 0.156 debit (1.00)
VIX was "fairly" low for the time, and daily stoch was overbought. Good time for a put diag.
8/4 ES 1292 VIX 13.91
STO AUG 1310C @ 4.65 delta 0.283
BTO SEP 1330C @ 5.75 delta 0.223 debit (1.10)
ES looked strong, so I put this one on with a target above the high of 6/2.
8/18 ES 1301 VIX 12.07
AUG options are still trading, but I will assume they expire worthless.
SEP 1200P are worth about 1.00, making the put diagonal a breakeven, even though the market is 24 points higher, and VIX is 2 points lower.
SEP 1330C is worth about 3.30, giving a profit of 2.20 points for the trade.
It was interesting to monitor the call diagonal. As the market approaches your short, you are simultaneously rooting for the increased profit and wondering if you will have to adjust since a little more movement will turn your profit into a loss.
I have to say, the ToS risk graphs are a HUGE educational tool in this regard. Anyone who doesn't have one should setup an account and try it out. You can use the software for free for 10 days before funding the account. Its a no-brainer.

7/25 ES 1277 VIX 14.3
STO AUG 1240P @ 6.00 delta 0.219
BTO SEP 1200P @ 7.00 delta 0.156 debit (1.00)
VIX was "fairly" low for the time, and daily stoch was overbought. Good time for a put diag.
8/4 ES 1292 VIX 13.91
STO AUG 1310C @ 4.65 delta 0.283
BTO SEP 1330C @ 5.75 delta 0.223 debit (1.10)
ES looked strong, so I put this one on with a target above the high of 6/2.
8/18 ES 1301 VIX 12.07
AUG options are still trading, but I will assume they expire worthless.
SEP 1200P are worth about 1.00, making the put diagonal a breakeven, even though the market is 24 points higher, and VIX is 2 points lower.
SEP 1330C is worth about 3.30, giving a profit of 2.20 points for the trade.
It was interesting to monitor the call diagonal. As the market approaches your short, you are simultaneously rooting for the increased profit and wondering if you will have to adjust since a little more movement will turn your profit into a loss.
I have to say, the ToS risk graphs are a HUGE educational tool in this regard. Anyone who doesn't have one should setup an account and try it out. You can use the software for free for 10 days before funding the account. Its a no-brainer.