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