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