This is a numerical study of gyrotactic microorganism, heat and mass transfer futures of hybrid Williamson nanofluid made up of water - Ag/MWCNT nanoparticles over swirling cylinder with Cattaneo-Christov heat flux. Suitable similarity transformations are presented to convert the governing partial differential equations into ordinary differential equations. The set of ordinary differential equations along with boundary conditions are solved by using the finite element technique. The sketches of swirling velocity, axial velocity, temperature, concentration and density of microorganism with individual pertinent quantities, such as volume fraction parameter of Ag nanoparticle (0.01 < phi 1 < 0.04), volume fraction parameter of MWCNT nanoparticle (0.01 < phi 2 < 0.04), Magnetic field parameter (0.1 < M < 0.7), Weissenberg number (0.5 < We < 0.8), Prandtl number (2.2 < Pr < 8.2), Reynolds number (0.5 < Re < 2.0), Chemical reaction parameter (0.1 < Cr < 0.7), Peclet number (0.1 < Pe < 0.7), Bio-convection Lewis number (1.0 < Sb < 1.6), Biot number (0.2 < Bi < 0.8), thermal relaxation parameter (0.5 < gamma < 2.0) and Suction parameter (0.1 < V-0 < 0.7), are depicted through graphs. Moreover, the numerical estimates of local density number of microorganisms, heat and mass transfer rates for different parameters are specified in a tabular form. The calculations show that local skin friction coefficient, Sherwood number and local density of microorganism intensify with increasing values of both volume fraction parameters (phi 1) and (phi 2). Also, the density of microorganisms and profiles of concentration are elevated in the fluid region with rising values of Weissenberg number. Temperature of hybrid nanofluid deteriorates with increasing values of thermal relaxation parameter.