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