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