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