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