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