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