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