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