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