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