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