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)(11,15)(12,20)(13,18)(14,16)(17,22)(19,24)(21,23)(25,26,31,33)(27,29,36,32)(28,34,37,38)(30,35,39,40)(1,2)(3,6)(4,7)(5,8)(9,11,14,13)(10,15,16,18)(12,19,22,21)(17,23,20,24)(25,27)(26,32)(28,30)(29,33)(31,36)(34,40)(35,38)(37,39)(1,3,5,4)(2,6,8,7)(10,16)(15,18)(17,20)(23,24)(26,33)(27,36)(28,37)(35,40)(9,10)(11,15)(12,17)(13,18)(14,16)(19,23)(20,22)(21,24)(25,28)(26,34)(27,30)(29,35)(31,37)(32,40)(33,38)(36,39) involution — undirected(1,3,5,4)(2,6,8,7)(9,12)(10,17)(11,19)(13,21)(14,22)(15,23)(16,20)(18,24)(25,29,31,32)(26,27,33,36)(28,35,37,40)(30,38,39,34)(1,4,5,3)(2,7,8,6)(9,13,14,11)(10,18,16,15)(12,21,22,19)(17,24,20,23)(25,30)(26,35)(27,28)(29,34)(31,39)(32,38)(33,40)(36,37)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.