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