One vertex per element, one color per generator, with an edge from x to x·s.
(10,11)(15,17)(16,18)(23,24)(26,30)(31,36)(32,37)(38,40) involution — undirected(1,2)(3,8)(4,6)(5,7)(9,10,14,11)(12,15,20,17)(13,16,22,18)(19,23,21,24)(27,33)(31,36)(34,39)(38,40)(1,3,5,6)(2,4,7,8)(25,26)(27,31)(28,32)(29,30)(33,36)(34,38)(35,37)(39,40)(1,2)(3,4)(5,7)(6,8)(9,11,14,10)(12,17,20,15)(13,16,22,18)(19,23,21,24)(25,27,29,33)(26,31,30,36)(28,34,35,39)(32,38,37,40)(1,2)(3,4)(5,7)(6,8)(9,12,14,20)(10,15,11,17)(13,21,22,19)(16,24,18,23)(25,26)(27,31)(28,32)(29,30)(33,36)(34,38)(35,37)(39,40)(1,4)(2,6)(3,7)(5,8)(9,13,14,22)(10,16,11,18)(12,19,20,21)(15,23,17,24)(25,28,29,35)(26,32,30,37)(27,34,33,39)(31,38,36,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.