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