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