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)(25,26,31,36)(27,30,35,32)(28,33,38,40)(29,39,37,34)(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)(26,32)(28,37)(29,38)(30,36)(31,35)(33,39)(34,40)(1,3,5,6)(2,4,7,8)(10,15)(14,21)(16,19)(22,23)(25,28,31,38)(26,33,36,40)(27,37,35,29)(30,34,32,39)(9,10)(11,14)(12,16)(13,15)(17,22)(18,21)(19,20)(23,24)(25,29,31,37)(26,34,36,39)(27,38,35,28)(30,33,32,40)(1,2)(3,4)(5,7)(6,8)(9,11)(10,14)(12,17)(13,18)(15,21)(16,22)(19,23)(20,24)(25,27)(26,30)(28,37)(29,38)(31,35)(32,36)(33,34)(39,40) 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)(25,30)(26,35)(27,36)(28,34)(29,33)(31,32)(37,40)(38,39)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.