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