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