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)(11,17)(12,21)(13,15)(14,18)(16,19)(20,22)(23,24)(25,26)(27,30)(28,34)(29,39)(31,33)(32,35)(36,40)(37,38) involution — undirected(1,3,5,4)(2,6,7,8)(9,11,16,13)(10,17,19,15)(12,20,14,23)(18,24,21,22)(25,27,32,29)(26,30,35,39)(28,37,31,36)(33,40,34,38)(9,12,16,14)(10,18,19,21)(11,20,13,23)(15,22,17,24)(25,28,32,31)(26,33,35,34)(27,36,29,37)(30,38,39,40)(9,13,16,11)(10,15,19,17)(12,20,14,23)(18,24,21,22)(25,29,32,27)(26,30,35,39)(28,36,31,37)(33,40,34,38)(1,4,5,3)(2,6,7,8)(9,14,16,12)(10,18,19,21)(11,20,13,23)(15,24,17,22)(25,30)(26,27)(28,38)(29,35)(31,40)(32,39)(33,36)(34,37)(1,2)(3,6)(4,8)(5,7)(9,15)(10,11)(12,22)(13,19)(14,24)(16,17)(18,20)(21,23)(25,31,32,28)(26,34,35,33)(27,36,29,37)(30,38,39,40)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.