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