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