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