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