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