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