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