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