Ok, because this is SMF, then you need on the "40G" Side (the S-Series) to have a QSFP+ PSM transceiver. This is only the transceiver, no cables, it's not a DAC either. On the other side (the x460-G2's) you will need to have regular SFP+ LR (assuming you need LR, ie < 10Km). I'm not aware of a solution for ER/ZR.
10326 QSFP+ PSM Optical Module QSFP+ (4X10GBASE) breakout optical module, MPO connector, 10km SMF link length
In between, that will depend on your fiber plant. We have in our pricelist a SMF MPO-to-4xLC patch cable.
10327 MPO to 4xLC breakout patch cable, SM 10m MPO to 4 x LC breakout patch cable, Single-Mode 10m
If you need SC/APC connector, you'll have to ask your usual fiber vendor.
If the x460-G2's are close enough to the S1, I'd encourage you to use MMF, that would be cheaper using QSFP+ SR4 or some DAC.