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