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