One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,14)(12,19)(13,15)(16,20)(17,23)(18,21)(22,24)(25,26,32,37)(27,35,29,33)(28,34,39,38)(30,31,36,40)(1,2)(3,8)(4,6)(5,7)(9,11,13,18)(10,14,15,21)(12,17,20,24)(16,22,19,23)(25,27,32,29)(26,33,37,35)(28,36,39,30)(31,38,40,34)(1,3,5,6)(2,4,7,8)(10,15)(14,21)(16,19)(22,23)(25,28,32,39)(26,34,37,38)(27,36,29,30)(31,35,40,33)(9,10)(11,14)(12,16)(13,15)(17,22)(18,21)(19,20)(23,24)(25,29,32,27)(26,35,37,33)(28,30,39,36)(31,34,40,38)(1,2)(3,4)(5,7)(6,8)(9,11)(10,14)(12,17)(13,18)(15,21)(16,22)(19,23)(20,24)(25,30)(26,31)(27,28)(29,39)(32,36)(33,38)(34,35)(37,40) involution — undirected(1,4)(2,6)(3,7)(5,8)(9,12,13,20)(10,16,15,19)(11,17,18,24)(14,22,21,23)(25,31)(26,36)(27,38)(28,35)(29,34)(30,37)(32,40)(33,39)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.