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