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