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