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