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