Just a jam along to the synth, easy and fun to play :)
Riff 1
G|-----------------------|
D|-----7-5---------------|
A|-5-5-----8-7-5-5-5-5-5-|
E|-----------------------|
[ Tab from: https://www.guitartabs.cc/tabs/s/swedish_house_mafia/one_btab_ver_2.html ]
Riff 2
G|---------------------------------------------------|
D|-5-5-5-5/8-8-8-8--8-5-8-12-12-12-12-10-10-10-10-10-|
A|---------------------------------------------------|
E|---------------------------------------------------|
Riff 3
G|-------------------------|
D|-------5-----------------|
A|-5-7-8---8-7-5-----------|
E|---------------7-5---3-5-|
Riff 1 X4
Riff 2 X4
Break
Riff 1 X10
Riff 3 X4
Riff 2 X3
Riff 3 X6
Riff 2 X2