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