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