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