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